One excuse for delays I have heard a little too frequently is suicide. So far in my life, two people have thrown themselves in front of my train, never once thinking of the consequences that my delay may have. Or the trauma that the poor driver must suffer. Or the cleaning crews that have to mop up afterwards.
You can always tell when these events happen while you are waiting at a station for a train, they are announced as “unfortunate incidents” when a train is delayed.